This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
In order to facilitate communication of video content over one or more networks, several coding standards have been developed. Video coding standards include ITU-T H.261, ISO/IEC MPEG-1 Video, ITU-T H.262 or ISO/IEC MPEG-2 Video, ITU-T H.263, ISO/IEC MPEG-4 Visual, ITU-T H.264 (also know as ISO/IEC MPEG-4 AVC), and the scalable video coding (SVC) extension of H.264/AVC. In addition, there are currently efforts underway to develop new video coding standards. One such standard under development is the multi-view video coding (MVC) standard, which will become another extension to H.264/AVC.
The latest SVC Joint Draft (8.0) is described in JVT-X201, “Joint Draft 8 of SVC Amendment”, 24th JVT meeting, Geneva, Switzerland, July. 2007, available from http://ftp3.itu.ch/av-arch/jvt-site/2007—06_Geneva/JVT-X201.zip.
In scalable video coding, a video signal can be encoded into a base layer and one or more enhancement layers constructed. An enhancement layer enhances the temporal resolution (i.e., the frame rate), the spatial resolution, or simply the quality of the video content represented by another layer or part thereof. Each layer together with all its dependent layers is one representation of the video signal at a certain spatial resolution, temporal resolution and quality level. In this document, we refer to a scalable layer together with all of its dependent layers as a “scalable layer representation”. The portion of a scalable bitstream corresponding to a scalable layer representation can be extracted and decoded to produce a representation of the original signal at certain fidelity.
Compressed multi-view video sequences require a considerable bitrate. They may have been coded for a spatial resolution (picture size in terms of pixels) or picture quality (spatial details) that are unnecessary for a display in use or unfeasible for a computational capacity in use while being suitable for another display and another computational complexity in use. In many systems, it would therefore be desirable to adjust the transmitted or processed bitrate, the picture rate, the picture size, or the picture quality of a compressed multi-view video bitstream. The current multi-view video coding solutions offer scalability only in terms of view scalability (selecting which views are decoded) or temporal scalability (selecting the picture rate at which the sequence is decoded.
The multi-view video profile of MPEG-2 video enables stereoscopic (2-view) video coded as if views were layers of a scalable MPEG-2 video bitstream, where a base layer is assigned to a left view and an enhancement layer is assigned to a right view. The ongoing multi-view video extension of H.264/AVC has been built on top of H.264/AVC, which provides only temporal scalability.